Horror videos show the moment a fire broke out at a New Year’s party at a Swiss ski resort, as witnesses said the blaze was started by a sparkler attached to a champagne bottle.

At least 40 people are feared dead and 100 were injured following the inferno at a bar called “Le Constellation” in the resort town of Crans-Montana, which is popular with international tourists.

The deadly fire was reportedly started accidentally by a woman who was being carried on another’s shoulders, holding a champagne bottle with a sparkler attached.The initial blaze in the bar triggered a so-called “flashover,” when all the combustible material in a room ignites at once, triggering multiple explosions, Swiss authorities said.

Interior view of the "Le Constellation" bar after a New Year's Eve explosion and fire.
The site of an explosion and fire at the Le Constellation bar, where the “entire ceiling of the bar caught fire.”via REUTERS
Fire at the bar "Le Constellation" in Crans-Montana, with the ceiling catching fire.
Witnesses said the deadly blaze was started by a sparkler attached to a champagne bottle.X/SuisseAlert

A promotional video from “Le Constellation” last year shows female night club workers carrying bottles of champagne with sparklers attached through the packed, low-ceilinged nightclub.

Another witness said the fire triggered a stampede as panicked bargoers surged up a narrow staircase from the venue, according to French outlet 24Heures.

“It was firework candles inside a champagne bottle that caused the explosion. The entire ceiling of the bar caught fire,” witness Victoria told French broadcaster BFMTV.

Beginning of a fire at the bar Le Constellation.
A grab from a video of before the fire started shows the blaze on the roof.X/SuisseAlert

The fire spread quickly through the bar, which holds up to 300 people, and within seconds, it was impossible to breathe.

“All the windows were black and opaque with smoke,” Victoria said. “Some people smashed windows to let in air.”

Terrifying video shared by Tyrone King, a visitor from New York, shows flames ripping through the bar, while screams are heard in the background.

Rescuers and firefighters at the site of a bar explosion in Crans-Montana, Switzerland.
Police officers block off the area in the resort town of Crans-Montana where a fire killed dozens.AFP via Getty Images

“We saw people smashing windows, running and screaming. Parents were racing up in their cars. It was like a horror movie,” another witness, Adrien, told BFMTV.

The basement bar reportedly had only one exit, a factor which had alarmed a previous visitor to the nightclub.

“I felt that an evacuation from the bar would be difficult. I even thought, if panic breaks out here, how would I get back to daylight?” the former visitor told Swiss outlet, Blick.

Many of the victims are feared to be teenagers, according to rescuers.

A fire consuming the Le Constellation bar and lounge.
The fire spread quickly through Le Constellation, which could hold up to 300 people.@AnnaDeMilanese

“It became apparent that there were also a large number of young patients among [the victims],” the head of the Swiss Air Rescue Helicopter team coordinating the response to the tragedy, Philipp Simmen, told Swiss broadcaster SRF.

Police officers inspect the fire site at the Le Constellation bar and lounge in Crans-Montana, Swiss Alps.
The fire occurred at a ritzy ski resort in Switzerland.AP

The operation to identify the dead is expected to take some time due to the scale of their injuries, according to Swiss media.